Solid ink or phase change ink imaging devices, hereafter called solid ink printers, encompass various imaging devices, such as printers and multi-function devices. These printers offer many advantages over other types of image generating devices, such as laser and aqueous inkjet imaging devices. Solid ink or phase change ink printers conventionally receive ink in a solid form, either as pellets or as ink sticks. A color printer typically uses four colors of ink (yellow, cyan, magenta, and black). The solid ink pellets or ink sticks, hereafter referred to as ink, sticks, or ink sticks, are delivered to a melting device, which is typically coupled to an ink loader, for conversion of the solid ink to a liquid. A typical ink loader includes multiple feed channels, one for each color of ink used in the imaging device. Each feed channel directs the solid ink within the channel towards a melting device located at the end of the channel. Each melting device receives solid ink from the feed channel to which the melting device is connected and heats the solid ink impinging on it to convert the solid ink into liquid ink that is delivered to a print head for jetting onto a recording medium or intermediate transfer surface.
Each feed channel may have a corresponding insertion opening to receive solid ink sticks. Alternatively, a solid ink jet printer may have a common insertion port in which solid ink sticks are loaded and then delivered to the channel that corresponds to the loaded ink stick. In both types of loading systems, the ink stick may be identified by detecting encoded indicia on the stick and comparing the detected data to data stored in the printer. The stored data identifies the ink sticks that are configured for use in the printer and the color of the ink sticks. Only if the detected data corresponds to the stored data is an ink stick accepted by the printer or released from the insertion opening or port to a feed channel in the printer.
In printers having an insertion opening for each feed channel, keyed openings may be placed over the insertion ports to help ensure a printer user properly places and orients ink sticks of the correct color or series in a feed channel. To accomplish this goal, each keyed opening has a unique shape. The ink sticks of the color corresponding to a particular feed channel have a shape corresponding to the shape of the keyed opening. The keyed openings and corresponding ink stick shapes exclude from each ink feed channel ink sticks of all colors except the ink sticks of the proper color for the feed channel. Unique keying shapes for other factors are also employed in keyed openings to exclude from a feed channel ink sticks that are formulated or intended for other printer models.
As the number of pages printed per minute increases for solid ink printers so does the demand for ink in the printer. To supply larger amounts of ink to printers, the cross-sectional area of the feed channels may be increased. Consequently, the insertion openings for the channels and the keyed plates covering the openings are likewise enlarged. These larger openings enable smaller solid ink sticks to pass through without engaging the keyed plates over the openings. Thus, solid ink sticks that do not conform to the appropriate color for a feed channel can be loaded into the feed channel and delivered to the melting device at the end of the feed channel. Even if the smaller stick is the correct color for the feed channel, its size may impair the ability of the stick to cooperate with guiding structure within the feed channel. Likewise, as common insertion ports increase in size, ink stick not configured for use in the printer may be inserted in the port. As long as these sticks have an identification code that corresponds to a code stored in the memory of an identification code detector, these sticks may be used in the printer. Thus, ensuring insertion ports in a solid ink printer are loaded only with ink sticks configured for transport within the feed channel is a desirable goal.